Internal combustion engine misfire analysis



Filed July 8, 19E-2 Tw. |Q NOUUN w m ./W mw mlm O on dw U8500 wkbh .MY MR ymA @H N W XMMS Litt. v UGQM H Q .uw J

In internal combustion engines, it is important to be able to accurately identify which of a plurality of cylinders is failing to fire. In engines of the diesel tiring type this is not a simple matter and it customarily involves considerable labor and time. Particularly in the large installations in automotive, railway and stationary power plants, this is a particular handicap at the outset of any repair work. By the present invention it now becomes possible to accurately and quickly locate which cylinder is at fault. Other objects and advantages of the invention will appear from the following description.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the Various ways in which the principle of the invention may be employed.

In said annexed drawing the sole ligure is a diagrammatic illustration of an embodiment of the invention.

In general, there is involved the providing a signal of each revolution of the engine and providing a signal of the ring of each cylinder, and correlating the two sets of signals. Thus, as illustrated in the drawing, the engine shaft 2 has a cam 3 which at each revolution actuates a contact switch 4, and this by its connected electric circuit 5 goes to a signal Coordinator 6. At the same time, by a tube 7 connecting into the exhaust manifold 1, the explosion pulsations are conducted to a means for converting gaseous pulsations into electric signals. This may be for instance an electromagnetic arrangement 8 involving a diaphragm 9 which vibrates at each gaseous pulsation from the manifold, and the diaphragm movement generates a current, in manner well known, and this is transmitted by a circuit 10. If the electromagnetic signal-former is of a construction not yielding sufliciently strong electric pulsations, a D. C. amplifier 11 may be interposed. The circuit proceeds in any case to the signal coordinator 6. While this may be on the order of an auditory arrangement, each set of signals having a responding means, it is generally preferable to provide coordinating means of visual type, and this may be an oscilloscope. For record, however, it is more desirable that the coordinator be an oscillograph with two pens 12, 13, the one being operated by the engine shaft revolution signal, and the other by the explosion pulsation signals. As the detail of such devices is well known, it is sufficient here to point out that the two pens cooperate with a record paper 14 on a drum or the like 15, and tracings are formed by the two sets of signals simultaneously and adjacent.

With an engine connected up as described in the foregoing, as the engine shaft 2 with its cam 3 closes the contact switch 4 at each revolution, a -signal is transmitted to the coordinator 6, and its pen 12 marks for example revolution peaks 16 on the record paper. Simultaneously, the explosion pulse from the exhaust manifold 1, generating electric pulsations transmitted to the coordinator 6 operate the pen 13 and the explosions register explosion peaks 17. Thus, for instance in the case of a four-cylinder two stroke cycle or eight-cylinder four stroke cycle engine, the explosion peaks are positioned .States Patent O ICC adjacent and within the scope of the revolution peaks 16, and a misring cylinder forms no explosion peak, and the order of normal tiring being known, the cylinder at fault is apparent.

Withal, the equipment and operation is free from complication, and examinations of engines are easily and quickly accomplished.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims, or the equivalent of such, be employed.

We therefore particularly point out and distinctly claim as our invention:

1. In apparatus for determining misfiring cylinders in a multcylinder internal combustion engine having a common shaft and a common exhaust manifold, the combination of: a cam on the engine shaft, a switch and electric circuit operated by said cam signaling each shaft revolution, electromagnetic means in communication with the exhaust manifold having an electric circuit forming an electric pulsation for each gaseous pressure pulsation in the manifold, an amplifier for such electric pulsations, and a recorder connected to such signal and pulsation means for providing a record simultaneously of the engine revolution signal and said pulsations.

2. In apparatus for determining misring cylinders in a multcylinder internal combustion engine having a common shaft and a common exhaust manifold, the combination of: a cam on the engine shaft, a switch and electric circuit operated by said cam signaling each shaft revolution, electromagnetic means in communication with the exhaust manifold having an electric circuit forming an electric pulsation for each gaseous pressure pulsation in the manifold, and a recorder connected to such signal and pulsation means for providing a record simultaneously of the engine revolution signal and said pulsations.

3. In apparatus for determining misring cylinders in a multcylinder internal combustion engine having a common shaft and a common exhaust manifold, the combination of: a cam on the engine shaft, a switch and electric circuit operated by said cam signaling each shaft revolution, electromagnetic means in communication with the exhaust manifold having an electric circuit forming an electric pulsation for each gaseous pressure pulsation in the manifold, and recording means connected to such signal and pulsation means for providing said engine revolution signal and said pulsations in a permanent record.

4. In apparatus for determining misring cylinders in a multcylinder internal combustion engine having a common shaft and a common exhaust manifold, the combination of: signal generating means responsive to revolutions of said shaft for producing electrical signals representative thereof, transducer means responsive to pressure pulsations within said manifold and operative to produce electrical pulses corresponding thereto, and recording means connected to said signal generating and transducer means to receive the signals and pulses respectively produced by the same, said recording means providing a combined record in which the pulses bear a predetermined relation to and are distinct from the revolution signals.

References Cited in the tile of this patent UNITED STATES PATENTS 1,051,931 Waindzioch Feb. 4, 1913 1,161,875 Morrow Nov. 30, 1915 2,119,166 Kadenacy May 31, 1931 2,236,422 Boley Mar. 25, 1941 2,622,441 Richardson et al Dec. 23, 1952 FOREIGN PATENTS 847,983 France Oct. 19, 1939 

